That explanation doesn't quite fit with historical opinion polls. It wasn't until 2000 that strong dislike of the opposing party shot up, and dislike had been slowly growing before that. But it is possible that the sudden change in trajectory was delayed by the 4 year election cycle, which puts politics in the fore of people's minds for durations that are too short for contempt to really snowball.
https://www.pewresearch.org/politics/2016/06/22/1-feelings-a...